networking - 无类别 IP 子网

Question

我想使用给定的 IP 地址进行子网划分，如下所示
192.168.10.0/25
我的要求是每个子网需要 30 个地址。
子网 0 的 nw 地址是什么？
是 192.168.10.0/27 还是 192.168.10.128/27 ？

Answer 1

ipcalc工具可以为您解答：

Address:   192.168.10.0          11000000.10101000.00001010.0 0000000
Netmask:   255.255.255.128 = 25  11111111.11111111.11111111.1 0000000
Wildcard:  0.0.0.127             00000000.00000000.00000000.0 1111111
=>
Network:   192.168.10.0/25       11000000.10101000.00001010.0 0000000 (Class C)
Broadcast: 192.168.10.127        11000000.10101000.00001010.0 1111111
HostMin:   192.168.10.1          11000000.10101000.00001010.0 0000001
HostMax:   192.168.10.126        11000000.10101000.00001010.0 1111110
Hosts/Net: 126                   (Private Internet)


Subnets

Netmask:   255.255.255.224 = 27  11111111.11111111.11111111.111 00000
Wildcard:  0.0.0.31              00000000.00000000.00000000.000 11111

Network:   192.168.10.0/27       11000000.10101000.00001010.000 00000 (Class C)
Broadcast: 192.168.10.31         11000000.10101000.00001010.000 11111
HostMin:   192.168.10.1          11000000.10101000.00001010.000 00001
HostMax:   192.168.10.30         11000000.10101000.00001010.000 11110
Hosts/Net: 30                    (Private Internet)


Network:   192.168.10.32/27      11000000.10101000.00001010.001 00000 (Class C)
Broadcast: 192.168.10.63         11000000.10101000.00001010.001 11111
HostMin:   192.168.10.33         11000000.10101000.00001010.001 00001
HostMax:   192.168.10.62         11000000.10101000.00001010.001 11110
Hosts/Net: 30                    (Private Internet)


Network:   192.168.10.64/27      11000000.10101000.00001010.010 00000 (Class C)
Broadcast: 192.168.10.95         11000000.10101000.00001010.010 11111
HostMin:   192.168.10.65         11000000.10101000.00001010.010 00001
HostMax:   192.168.10.94         11000000.10101000.00001010.010 11110
Hosts/Net: 30                    (Private Internet)


Network:   192.168.10.96/27      11000000.10101000.00001010.011 00000 (Class C)
Broadcast: 192.168.10.127        11000000.10101000.00001010.011 11111
HostMin:   192.168.10.97         11000000.10101000.00001010.011 00001
HostMax:   192.168.10.126        11000000.10101000.00001010.011 11110
Hosts/Net: 30                    (Private Internet)



Subnets:   4 
Hosts:     120

另外，地址192.168.10.128超出了原来的范围/25！